/*******************************************************************************
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 ******************************************************************************/
package org.apache.nutch.api.impl;

import java.util.Collections;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.atomic.AtomicInteger;

import org.apache.commons.collections.MapUtils;
import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.nutch.api.ConfManager;
import org.apache.nutch.api.model.request.NutchConfig;
import org.apache.nutch.api.resources.ConfigResource;
import org.apache.nutch.util.NutchConfiguration;

import com.google.common.collect.Maps;

public class RAMConfManager implements ConfManager {
	private Map<String, Configuration> configurations = Maps.newConcurrentMap();

	private AtomicInteger newConfigId = new AtomicInteger();

	public RAMConfManager() {
		configurations.put(ConfigResource.DEFAULT, NutchConfiguration.create());
	}

	public Set<String> list() {
		return configurations.keySet();
	}

	public Configuration get(String confId) {
		if (confId == null) {
			return configurations.get(ConfigResource.DEFAULT);
		}
		return configurations.get(confId);
	}

	public Map<String, String> getAsMap(String confId) {
		Configuration configuration = configurations.get(confId);
		if (configuration == null) {
			return Collections.emptyMap();
		}

		Iterator<Entry<String, String>> iterator = configuration.iterator();
		Map<String, String> configMap = Maps.newTreeMap();
		while (iterator.hasNext()) {
			Entry<String, String> entry = iterator.next();
			configMap.put(entry.getKey(), entry.getValue());
		}
		return configMap;
	}

	public void setProperty(String confId, String propName, String propValue) {
		if (!configurations.containsKey(confId)) {
			throw new IllegalArgumentException(
					"Unknown configId '" + confId + "'");
		}
		Configuration conf = configurations.get(confId);
		conf.set(propName, propValue);
	}

	public void delete(String confId) {
		configurations.remove(confId);
	}

	@Override
	public String create(NutchConfig nutchConfig) {
		if (StringUtils.isBlank(nutchConfig.getConfigId())) {
			nutchConfig
					.setConfigId(String.valueOf(newConfigId.incrementAndGet()));
		}

		if (!canCreate(nutchConfig)) {
			throw new IllegalArgumentException("Config already exists.");
		}

		createHadoopConfig(nutchConfig);
		return nutchConfig.getConfigId();
	}

	private boolean canCreate(NutchConfig nutchConfig) {
		if (nutchConfig.isForce()) {
			return true;
		}
		if (!configurations.containsKey(nutchConfig.getConfigId())) {
			return true;
		}
		return false;
	}

	private void createHadoopConfig(NutchConfig nutchConfig) {
		Configuration conf = NutchConfiguration.create();
		configurations.put(nutchConfig.getConfigId(), conf);

		if (MapUtils.isEmpty(nutchConfig.getParams())) {
			return;
		}
		for (Entry<String, String> e : nutchConfig.getParams().entrySet()) {
			conf.set(e.getKey(), e.getValue());
		}
	}

}
